An electrostatic discharge (ElectroStatic Discharge: ESD) results, for example, in a current peak of 30 amps in one nanosecond followed by a current of 10 amps over 10 nanoseconds.
A first approach for protection consists in using a single protection circuit, for example a large-sized triac, associated with triggering means. However, although such a circuit is effective for absorbing strong ESD discharges, it is not efficient at triggering rapidly in the presence of weak ESD discharges.
A second approach consists in using several ESD protection circuits, of smaller size, each associated with a triggering circuit. Such protection means are this time efficient in the presence of weak ESD discharges but not effective in the presence of strong ESD pulses because the triggering of a single protection circuit does not guarantee a triggering of the other protection circuits.
An example of an ESD protection structure is described in the European patent application published under the number 2 246 885 A1, incorporated herein by reference. This structure comprises a set of identical cells arranged as a ring matrix in such a way as to form triplets of triggerable triacs. As the anode-cathode distances are not identical for all of the triacs of a triplet, this can be penalizing in terms of efficiency. Moreover, in certain cases, dead zones can exist between the consecutive triggerings of several triplets which can result, during the ESD event, in overvoltage peaks at the terminals of the component or of the contact to be protected.